The package validate on save by default (you can disable this behavior in the settings). You can also use the comma,d
validateOnSave: Make a validation each time you save an HTML file.
validateOnChange: Make a validation each time you change an HTML file.
hideOnNoErrors: Hide the panel if there was no errors.
useFoldModeAsDefault: Fold the results panel by default.
cssProfile: Profile to use for CSS file validation (default: css3). For CSS files only
cssMedia: Media to use for CSS file validation (default: all). For CSS files only
cssReportType: CSS Report severity (default: normal). For CSS files only
With the success of Atom, it's really difficult to choose keybindings that will not enter in conflict whit anyone else's packages, so I have removed the default keystrokes and let the keymap empty to let you set your own keybindings.
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.